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<h1 class="title">Explanation of start of release changes</h1>
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<nav id="TOC" role="doc-toc">
<ul>
<li><a href="#overview" id="toc-overview">Overview</a></li>
<li><a href="#details-and-file-updates"
id="toc-details-and-file-updates">Details and file updates</a>
<ul>
<li><a href="#meta-data-files" id="toc-meta-data-files">Meta-data
files</a></li>
<li><a href="#src-files" id="toc-src-files"><code>src</code>
files</a></li>
<li><a href="#test-files" id="toc-test-files"><code>test</code>
files</a></li>
</ul></li>
</ul>
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<h2 id="overview">Overview</h2>
<p>The start of release changes, the changes that turn JDK <em>N</em>
into JDK (<em>N</em>+1), are primarily small updates to various files
along with new files to store symbol information to allow
<code>javac --release N ...</code> to run on JDK (<em>N</em>+1).</p>
<p>The updates include changes to files holding meta-data about the
release, files under the <code>src</code> directory for API and tooling
updates, and incidental updates under the <code>test</code>
directory.</p>
<h2 id="details-and-file-updates">Details and file updates</h2>
<p>As a matter of policy, there are a number of semantically distinct
concepts which get incremented separately at the start of a new
release:</p>
<ul>
<li>Feature value of <code>Runtime.version()</code></li>
<li>Highest source version modeled by
<code>javax.lang.model.SourceVersion</code></li>
<li>Highest class file format major version recognized by the
platform</li>
<li>Highest
<code>-source</code>/<code>-target</code>/<code>--release</code>
argument recognized by <code>javac</code> and related tools</li>
</ul>
<p>The expected file updates are listed below. Additional files may need
to be updated for a particular release.</p>
<h3 id="meta-data-files">Meta-data files</h3>
<ul>
<li><code>jcheck/conf</code>: update meta-data used by
<code>jcheck</code> and the Skara tooling</li>
<li><code>make/conf/version-numbers.conf</code>: update to meta-data
used in the build</li>
</ul>
<h3 id="src-files"><code>src</code> files</h3>
<ul>
<li><code>src/hotspot/share/classfile/classFileParser.cpp</code>: add a
<code>#define</code> for the new version</li>
<li><code>src/java.base/share/classes/java/lang/classfile/ClassFile.java</code>:
add a constant for the new class file format version</li>
<li><code>src/java.base/share/classes/java/lang/reflect/ClassFileFormatVersion.java</code>:
add an <code>enum</code> constant for the new class file format
version</li>
<li><code>src/java.compiler/share/classes/javax/lang/model/SourceVersion.java</code>:
add an <code>enum</code> constant for the new source version</li>
<li><code>src/java.compiler/share/classes/javax/lang/model/util/*</code>
visitors: Update <code>@SupportedSourceVersion</code> annotations to
latest value. Note this update is done in lieu of introducing another
set of visitors for each Java SE release.</li>
<li><code>src/jdk.compiler/share/classes/com/sun/tools/javac/code/Source.java</code>:
add an <code>enum</code> constant for the new source version internal to
<code>javac</code></li>
<li><code>src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/ClassFile.java</code>:
add an <code>enum</code> constant for the new class file format version
internal to <code>javac</code></li>
<li><code>src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/Target.java</code>:
add an <code>enum</code> constant for the new target version internal to
<code>javac</code></li>
<li><code>src/jdk.compiler/share/classes/com/sun/tools/javac/processing/PrintingProcessor.java</code>
update printing processor to support the new source version</li>
<li>The symbol information for <code>--release</code> is stored as new
text files in the <code>src/jdk.compiler/share/data/symbols</code>
directory, one file per module. The README file in that directory
contains directions on how to create the files.</li>
</ul>
<h3 id="test-files"><code>test</code> files</h3>
<ul>
<li><code>test/langtools/tools/javac/api/TestGetSourceVersions.java</code>:
add new <code>SourceVersion</code> constant to test matrix.</li>
<li><code>test/langtools/tools/javac/classfiles/ClassVersionChecker.java</code>:
add new enum constant for the new class file version</li>
<li><code>test/langtools/tools/javac/lib/JavacTestingAbstractProcessor.java</code>
update annotation processor extended by <code>javac</code> tests to
cover the new source version</li>
<li><code>test/langtools/tools/javac/preview/classReaderTest/Client.nopreview.out</code>
and
<code>test/langtools/tools/javac/preview/classReaderTest/Client.preview.out</code>:
update expected messages for preview errors and warnings</li>
<li><code>test/langtools/tools/javac/versions/Versions.java</code>: add
new source version to the set of valid sources and add new enum constant
for the new class file version.</li>
</ul>
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